<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>浮空于定位</title>
</head>
<style>
    .header,aside,.footer,.section{
        border: 1px solid yellow;
        background-color: pink;
    }
    .float-div{
        border: 1px solid yellow;
        background-color: rgb(247, 0, 255);
    }
    .header{
        height: 200px;
    }
    .aside,.section{
        height: 500px;
    }
    .aside{
        width: 400px;
        float: left;
    }
    .section{
        width: 1902px;
    }
    .footer{
        height: 200px;
    }
    .float-div{
        height: 150px;
        width: 150px;
        position: absolute;
        top: 200px;
        left: 400px;
    }
</style>
<body>
    <header class="header">Header</header>
    <aside class="aside">Aside</aside>
    <section class="section">
        section
        <div class="float-div">Floatdiv</div>
    </section>
    <footer class="footer">footer</footer>

</body>
</html>